Falling from height known as one of the most important factors that leads to fatal accidents in the construction industry.The purpose of this study was to investigate and identify the effective factors in the occurrence of falling from height accidents in the construction projects and determine the causal relationships between organizational, individual and environmental factors.In this research, the surveyed population was the workers of five construction projects of a gas refinery in south of Iran from ۲۰۱۱ to ۲۰۱۵. Using the Integrated Management System (IMS) information, factors and sub-factors affecting the occurrence of falling from height accidents in the construction projects were determined. Then, a semi-comparative questionnaire based on the DEMATEL technique was designed and distributed among ۱۰ experts at two different periods. Based on the expert's opinions, the identified factors and sub-factors were classified into three main factors and fourteen sub-factors, respectively. Then, the causal relationships between each the effective factor were identified, using DEMATEL technique.The results of DEMATEL technique revealed that the individual factors were considered to be the most important criteria, as it has acquired the maximum (𝐷+𝑅) value, i.e., ۳۶.۶۸۹ whereas, organizational factors had scored the least, i.e., ۳۵.۱۸۰. Accordingly, organizational factors and their sub-factors had a substantial effect on the falling from height accidents and were considered as causal variables (D-R>۰), while, the indices of individual and environmental factors were the effect variables (D-R<۰). So that, mutual understanding was an organizational sub-factor that had the highest impact on the occurrence of falling from height and has been identified as a causal variable.Generally, it is necessary to consider specific plans such as stress management and safety culture programs in order to reduce unsafe conditions in the construction projects.